Step 1: Why?
Also it would make him shut the heck up until someone was in the right spot for him to yell at them.
Step 2: Materials
I found some thin 2-sided circuit board material. (thin copper on each side of thin fiberglass board. But I don't know where that is now, so...
Or use paper or thin plastic as the insulator and copper tape or thin copper sheet for the conductors. I think stained glass people use copper tape to solder over.
Then some 2 conductor insulated wire.
Soldering iron, solder, wire stripper, scissors (but not the 'good scissors'), and glue.
And some kind of switch.
Step 3: Cut, Solder, Do
Cut the conductor strips smaller.
Sandwich together. Glue or stick the conductors on if they have adhesive.
Solder on the wires.
Solder on wires first so the heat doesn't melt stuff.
Step 4: The Switch
Or a reed switch
Or a backward reed switch.
Or a mercury switch.
Or a pressure mat switch that turns on when stepped on.
Or a clothes pin with conductors held apart by an insulator that gets pulled out by a tripwire.
Or just bare wires that you touch together.